Main Thread Panic when swarmed with clients

[drdrsh]

thread 'main' panicked at 'attempt to add with overflow', src/main.rs:289:17
stack backtrace:
   0: rust_begin_unwind
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:584:5
   1: core::panicking::panic_fmt
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/panicking.rs:142:14
   2: core::panicking::panic
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/panicking.rs:48:5
   3: pgcat::main::{{closure}}
             at ./src/main.rs:289:17
   4: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/future/mod.rs:91:19
   5: tokio::park::thread::CachedParkThread::block_on::{{closure}}
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/park/thread.rs:263:54
   6: tokio::coop::with_budget::{{closure}}
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/coop.rs:102:9
   7: std::thread::local::LocalKey<T>::try_with
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/thread/local.rs:445:16
   8: std::thread::local::LocalKey<T>::with
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/thread/local.rs:421:9
   9: tokio::coop::with_budget
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/coop.rs:95:5
  10: tokio::coop::budget
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/coop.rs:72:5
  11: tokio::park::thread::CachedParkThread::block_on
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/park/thread.rs:263:31
  12: tokio::runtime::enter::Enter::block_on
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/runtime/enter.rs:151:13
  13: tokio::runtime::thread_pool::ThreadPool::block_on
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/runtime/thread_pool/mod.rs:73:9
  14: tokio::runtime::Runtime::block_on
             at ~/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.16.1/src/runtime/mod.rs:477:43
  15: pgcat::main
             at ./src/main.rs:298:5
  16: core::ops::function::FnOnce::call_once
             at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/ops/function.rs:248:5

[zain-kabani]

We might want to consider setting max client connections at some point

[levkk]

Ah yeah, I forgot we're keeping this one alive until the client disconnects. Good catch. I'd make it a usize to avoid this problem forever.

[levkk]

On second thought....we're only sending 1 and 0 through this channel. Why would it overflow?

[levkk]

Ah yes, because total_clients becomes an i8. Wow! Subtle.

[levkk]

We might want to consider setting max client connections at some point

That limit ended up always being a file descriptor issue, not anything to do with the proxy itself. All of our data structures should be O(1), so number of clients shouldn't matter.